فهرست مطالب mhammadjavad goodarzi

Incremental dynamic analysis is one of the most common analyses in evaluating the seismic performance of structures. Usually, in this method, the influence of uncertainties is ignored and only by considering different records, it attempts to evaluate the uncertainty of seismic load. In this research, an attempt was made to investigate the effect of random variables on these curves by using two methods Monte Carlo and Tornado diagram. A 10-story steel frame with a dual bending frame system with a divergent brace was selected and then the effect of uncertainties on its IDA curves was investigated. First, by using the Monte Carlo method, the sensitivity of the IDA curve of the Bam earthquake record with respect to six random variables including yield stress of steel, dead load, live load, span length, damping ratio and elastic modulus was investigated. Then, using the tornado diagram method, the sensitivity of these variables on the average IDA curves obtained from 18 records of different earthquakes was investigated. The results demonstrated that dead load and yield stress had the greatest impact on random variables. In addition, the degree of sensitivity of random variables increased with the increase of spectral acceleration. The comparison of the tornado diagram method with the Monte Carlo method illustrated that the tornado diagram method with a maximum error of 12.4% has a good accuracy in evaluating seismic sensitivity.

Evaluating the seismic performance of structures is one of the interests and responsibilities of structural and earthquake engineers. The eccentric bracing system has always been one of the most important and widely used structural systems due to its high strength, stiffness and ductility. These structures are usually designed with horizontal shear and bending links. In this research, using nonlinear dynamic analysis, the seismic response and performance of these structures under near-field records with and without vertical components in addition to considering the effect of soil-structure interaction were investigated. Therefore, three types of frames of 4, 8 and 12 floors were designed and modeled non-linearly using the finite element method in Perform-3D software. Maximum displacement and displacement of roof residue, floor drift and base shear of these structures were selected and studied as engineering demand parameters. The results showed that the structure with horizontal shear link had much better responses than the frame with horizontal bending link. In addition, the effect of soil-structure interaction increased the roof displacement and reduced the base shear on the structure.